Buildings in which people work and live have systems that monitor and sustain the comfort level of the building environment. Such systems include heating, ventilation and air conditioning (HVAC) systems, lighting systems, as well as others. HVAC and lighting systems have existed, at least at some level, for thousands of years.
HVAC systems have over time become sophisticated, resulting in systems that are able to maintain careful balances of humidity and temperature, as well as provide adequate fresh air within buildings. Suitable temperature, humidity and oxygen levels contribute to the indoor environmental quality of a building or work place. Good environmental quality can translate to better productivity and health of the occupants.
One often overlooked element of environmental control is lighting control. Lighting systems in their basic form consist of light fixtures that provide a predetermined and constant output. The light fixtures may typically be turned on or off as need using manual switches. Such rudimentary manual control can result in tremendous inefficiency because it relies on unpredictable human control to ensure that the lighting is turned off when humans are not present. As a result, lights are typically left energized for substantial amounts of time that humans are not present.
To address these inefficiencies, some systems incorporate occupancy sensors that can automatically turn off the lights in the absence of human occupants. The occupancy sensors also automatically turn lights back on when human occupants are again detected.
While the current methods of lighting control using occupancy sensing improves energy efficiency of lighting systems in facilities, there is nevertheless a need for improved efficiency.